Clutch control



A. W. OFELDT CLUTCH CONTROL Nam 21, 195@ 2 Sheets-Sheet 1 Filed Sept. 16, 1944 @Ihliwr l I I I N VEN TOR. Aw 'wi Wfifeldfi A. W. OFELDT CLUTCH CONTROL 2 Sheets-Sheet 2 Filed Sept. 16, 1944 wwk NW Q N% u ww M Patented Nov. 21, 1950 RATE F F I 'C CLUTQH CONTROL August Ofeldt, Hackensack, N. .12, assignor to Bendix Aviation Corporation, Teterboro, N. J., a. demarcation: of: Delaware" Application September 16, 1944, Serial No, 554,499

Q GIaims'. (Cl. 1'92--5'5 )J My invention relates to drivesand more; particularly to drivesof the clutch type.

One of the objects of my invention" is to provide a drive of the clutch type equipped with means responsive to anoverloading of the driven means for rendering the; clutch inefiecti ve and in a manner to preclude burning of" the clutch.

Another object or my invention is to provide a drive of the foregoing described character which is simple in construction, durable in use, eiii'cient in operation and economical in manufacture.

With the above and other objects in view; as

will hereinafter appear; the invention consists in the combination, and arrangement or parts hereinafter set forthand illustrated in the accompanying' drawings; f om which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art; 7

Referring to the drawings; wherein like refer"- ence characters designate like parts throughout the several views,

Figure" I is. a sideeievati'on of my invention i1- lustrated' in conjunction with a. retractable land:- ing: gear of an aircraft.

Figure 2 is a sectional view taken on a line 2'-2' of Figure I.

Figure 3" is a sectional view taken on a line 3-4 of Figure 2" and on an enlarged scale:

Figure 4 is a, detail sectional view of a portion of one end of the housing and illustrating the bearing for the carrier.

As illustrated in Figure I of the drawings, the invention is illustrated in conjunction. with a retractable landing, gear H!" of an aircra t and which gear includes a. Wheel ti mounted on an axle l-2 equipped with a shock. absorber f3 pivotall'y connected to the wingv [4' of. the craft The wheel [I ismoved fromthe position illustrated to a retracted. position within asuitable recess (not shown) in the wing M by means of astrutbar IS, the latter being pivotall y connected at one end to the axle: 12'- and at'the. other end to a threaded collar ll mounted for recipro cal movement on a threaded shat-t [8 the pitch of the threads of the shaft being suchthat the wheel it may berigidly secured in: any selected position. The ends or the shaftl'8' area journalled in hearings" to and with: one endhaving mounted thereon a gear 211- for cheating rotation of the shaft and pivoting of the wheel i I to raised or lowered positions, as the case may be; The gear 20 meshes with a drive gear 2; keyed to a'jack 2; shaft 22 having fi-Xedthereto a driven gear 23, the jack shaft being mounted within theWi ng' I' l by means of bearings 24. A reversible electrical motor 25 is also mounted within the for operating the landing gear l d in a manner hereinafter more fully described. Inasmuch as the foregoing'described elements or components form no part of the present inventionper se, a more detailed disclosureof the same is not believed necessary, components or' an" assembly of a similar type being disclosed in U. S Patent No. 2,262,330.

A- driving mechanism is connected between the motor and the landing gear I-ll and comprises a cylindrical. housing 3I- which is attached to the wing I 4 and formed, at one end, with a diametrically reduced section 32 embracing aboss of the motor 25, through which the drive shaft 33- thereof extends, a set screw'being employed to maintain the housing in fixed relation with respect to the motor. Internally; the housing 3! is provided with a plurality of rollerbearings 34 35 and 36- arrangedin predetermined spaced relation for a purpose tobe later described.

Disposed within the housing 3! is a clutch assembly 37 comprising a double cup-shaped casing 38 formed with a radial dividing wall 39' defining a pair of inner and outer chambered portions 40 and M respectively. The outer portion 4! is of a greater diameter than the inner portion 40 and receives therein .a, multiple disc clutch pack 42 formed with a central opening.

A clutch actuating unit designated generally by the numeral t4 comprises a cup-shaped portion 45 nested within the central opening of the pack 42 and an outwardly extending annular lip 4E rotatably mounted in the bearing 3c. Ih-e.

lip 46 is provided with a shoe i! for engaging one end of the clutch pack 42, the discs of said pack being splined to the portion ll and the cupshaped portion- 35 in alternate relation to eiiect clutched and declutched relation between the cup-shaped casing 38 and the cup-shaped portion 45 of-the unit 44' when the pack is compressed and released respectively by the shoe 4? as hereinafter made apparent. A plate 48 is secured to the lip-46 by means of screws t9 and encloses the outer end of the cup-shaped portion d5, said plate having fixed thereto an external driving gear meshing with the gear 23 on the jack shaft 22,

The dividing wall 39 of the cup-shaped casing 38 has threaded therein the inner end of a stud or bolt Ell which extends through a central axiall3 aligned opening in the adjacent end wall or bottom 52 of the cup-shaped portion ti; and has 55 sleeved thereon a coil spring 5'3 having one end 56 which extend through said wall 38 and engage A clutch actuator means generally indicated by the numeral 60 is disposed within the housing 3| and comprises a pair of axially spaced internally threaded sleeves SI and 62 respectively, and with the latter sleeve being journalled in the bearing 35 and formed with a section keyed to the motor shaft 33 for effecting unitary rotation of the shaft and sleeve. The sleeve 6| is disposed within the chambered portion 49 which is rotatably mounted in the bearing 35 and is splined to the portion 40 for rotation therewith and axial movement relative thereto as hereinafter more clearly described.

A double acting screw member or right-andleft screw shaft 63 connects the sleeves El and 62 together and is formed with a tool receivin intermediate section 64 and has its reversibly threaded end sections 65 and 66 threaded within the sleeves 6! and 62 respectively for unitary axial movement in opposite directions depending upon the direction of rotation of the latter. The leads of the threads of the end sections 65 and B6 are such as to normally establish and maintain unitary rotation between the sleeves and member in conformity to a pie-established load value on the friction clutch pack, the exceeding of which value, by load imposed upon the lip '25, serves to eifect axial movement of either the sleeve 5| relative to the end section 65 oraxial movement of the end section 66 relative to the sleeve 62 depending upon the direction of rotation of said shaft 63 and thus moves the sleeve 6| towards the dividing wall 39 of the casing 38.

When the sleeve Si is axially moved towards the wall 39 in the foregoing described manner, the pins 56 will also be moved and effect actuation of the clutch actuating unit 44 to quickly release the cooperating discs of the clutch pack by reason of the abrupt angular position of the threads. Such a release of the clutch pack, as thus described, permits an accelerated and appreciable axial displacement of the discs relative to each other thereby releasing their frictional engagement thus eliminating disc burning, it being understood that the tension of the spring 53 is adjusted in a manner to impose a greater load value on the pack than the load on the clutch actuator means. From the foregoing, it will be apparent that when the landing gear reaches its retracted position, an overload, in excess of the value established for the clutch actuator means, will be imposed upon the lip 46 with the result that the sleeve 5| will be actuated to effect actuation of the clutch actuating unit and thereby release the cooperating discs of the clutch pack to permit continued operation of the motor without the chances of burning the clutch discs or until such time as the motor has been cut off. When the landing gear is operated from retracted to its extended position, by reversing the direction of rotation of the motor 25, a similar overload is imposed upon the lip d5 when said gear reaches its extended position with the result that a like operation of the parts is had.

As illustrated in Figures 3 and 4, the inner and outer races El and 58 of the bearing 38 are provided with radially disposed end flanges 69 and 76, respectively, for embracing the rollers l I, each of the roller paths being of a greater Width than the rollers to permit axial movement of the lip 4'6 relative to the housing 3| when the clutch operating unit 44 is actuated for releasing and compressing the clutch pack 42.

Without further elaboration the foregoing Will so fully explain the invention that others may, by applying current knowledge, readily ada t the same for use under various conditions of service. Moreover, it is not indispensable that all the features of the invention be used conjointly since they may be employed advantageously in various combinations and sub-combinations.

It is obvious that the invention is not confined to the herein described use therefor as it may be utilized for any purpose to which it is adaptable. It is therefore to be understood that the invention is not limited to the specific construction as illustrated and described as the same is only illustrative of the principles of operation, which are capable of extended application in various forms, and that the invention comprehends all construction within the scope of the appended claims.

What is claimed is: I

1. In combination, a housing, a reversible motor including a shaft extending into said housing, and meansin said housing including an axially stationary coupling sleeve splined to said shaft for rotation therewith and having an internally screw threaded portion, a bearing rotatively supporting said sleeve, an axially movable second rotatable coupling sleeve having opposite internal screw thread,'a shaft having opposite end lengths in and cooperatively threaded to said sleeves, respectively, a member including oppositely facing cup portions of different diameters having a mutual bottom wall therebetween, the cup of smaller diameter being disposed about and splined to said second sleeve for rotation therewith, a bearing cooperating with said smaller cup and rotatably supporting said member, torque limiting means including a friction disc pack in the cup of larger diameter, a third cup'surrounded by said pack having a closed end wall next to said bottom wall and a shoe at the open end of the third cup axially opposite one end of said pack, discs of said pack being splined to said larger cup and said third cup, respectively, for rotation therewith and axial movement relative thereto, a bolt concentric with said discs in said third cup fixed to said closed end, a spring tensioning member around said bolt, a spring around said bolt between said closed end and said tensioning member for urging said shoe against said pack and pressing the pack at its other end against said bottom wall, a bearing'for, and providing for axial movement of, said third cup, slide pin means in said bottom wall through the intermediary of which said second sleeve moves said third cup against the action of said spring to relieve the pressure of said shoe on said pack, and a driven gear outside said housing and connected to said third cup for rotation thereby.

2. In combination, a motor including a shaft, an internally screw threaded axially stationary coupling sleeve rotatable by said shaft, an axially 5 movable and oppositely internally screw threaded second coupling sleeve, a shaft between and having opposite end lengths cooperatively threaded to said sleeves, respectively, a member including oppositely facing cup portions of dif- 5 ferent diameters having a mutual bottom wall, the smaller cup being rotatable with said second sleeve, torque limiting means including a friction disc pack in the larger cup, a third cup sursaid third cup fixed to said closed end, a spring tensioning member on said bolt, a spring between said closed end and said tensioning member for urging said shoe against said. pack to press the pack against said bottom wall, means slidable in said bottom wall by which said second sleeve moves said third cup against the, action of said spring to relieve the. pressure of said shoe on said pack, and a member rotatably driven said third cup.

3'. In combination, a driving shaft, an axially stationary screw threaded coupling element rotatable by said shaft, an axially movable op-. positely threaded second coupling element, a shaft between said elements having portions cooperatively threaded thereto, respectively, a member including oppositely facing cup portions having a mutual bottom wall, one of said cups being rotatable with said second element, torque limiting means including normally frictionally engaging means in the other of said cups, a third cup surrounded by said friction means having a closed end next to said wall and a shoe at the open end of the third cup axially opposite said friction means, elements of said friction means being connected to said one and said other cup, respectively, for rotation therewith and movement relative thereto for varying the friction therebetween, spring means concentrically disposed within said discs in said third cup for urging said shoe to bias said friction elements together, means adapted for actuation by said sec ond coupling element in response to axial movement thereof against the action of said spring means to relieve the pressure of said shoe on said friction means, and a member rotatably driven by said third cup.

4. In combination in a transmission mechanism, a reversibly rotatable driving input member, an axially stationary coupling rotatable by said member, a second rotatable coupling adapted for axial movement, a driven output member, torque limiting means including a multiplicity of friction discs operatively connected between said output member and said second coupling, means normally maintaining the torque of said limiting means at a predetermined value, spring actuating means concentrically mounted Within said friction discs operable by said second coupling in response to the aforesaid axial movement of this second coupling to aliect said maintaining means to reduce said value, and means cooperatively connected to and between said coupling members adapted to normally cause driving of said output member by said input member in either direction of rotation of the latter at loads under said value and responsive to the imposition on said output member of a load greater 6 than said value for causing the aforesaid axial movement of said second coupling.

5-. In combination in a transmission mechanism, a reversibly rotatable driving input member, an axially stationary coupling rotatable by said member, a second rotatable coupling adapted for axial movement, a driven output member, torque limiting means including a multiplicity of friction discs operatively connected between said output member and said second coupling, compressible means concentrically disposed within 'said friction discs normally maintaining the torque of said limiting means at a predetermined 'valueand responsive to said axial movement for reducing said value, and means cooperatively connected to and between said coupling members adaptedto normally cause driving of said output member by said input member in either direction of rotation of the latter'at loads under said value and responsive to the imposition on said output member of a load greater than said value for causing the aforesaid axial movement of said second coupling.

6-. In combination in a transmission mechanism, areversibly rotatable driving input member, an axiallystationary coupling rotatable by said member, a second rotatable coupling adapted foraxial movement, a driven output member, torque limiting means including a multiplicity of friction discs operatively connected between said output member and said second coupling, normally maintaining said torque at a predetermined value and responsive to the aforesaid axial movement of said second coupling for reducing said value, and spring means concentric within said friction discs cooperatively connected to and between said coupling members adapted to normally cause driving of said output member by said input member in either direction of rotation of the latter at loads under said value and responsive to the imposition on said output member of a load greater than the aforesaid value for causing'said axial movement of said second coupling.

7. In combination in a transmission mechanism, a reversibly rotatable driving input member, an axially stationary coupling rotatable by said member, a second rotatable coupling adapted for axial movement, a driven output member, torque limiting means operatively connected between said output member and said second coupling, normally maintaining said torque at a predetermined value, a control member responsive to the aforesaid axial movement of said second coupling for reducing said value, and spring means biasing said control member in 0pposi tion to the axial movement of said second coupling so as to normally cause driving of said output member by said input member in either direction of rotation of the latter at loads under said value and means including a screw having right and left hand threads responsive to the imposition on said output member of a load greater than said value for causing the aforesaid axial movement of said second coupling and adjustment of said control member to reduce said value.

8. In combination in a transmission mechanism, a reversibly rotatable driving input member, a rotatably driven output member, and connecting means between said members including torque limiting means normally maintaining the torque at a predetermined value, and load responsive means to efiect said limiting means in ber to reduce said value upon imposition on said output member of a load greater than said value, the last said means including predetermined compressible means, a screw having right and left hand screw threads, a pair of movable ele ments cooperating with said threads respectively, one of said elements rotatably connected to said input member, the other of said elements movable axially upon imposition of said load on said output member, a control member to afiect said limiting means, and said control member biased by said compressible means in opposition to the axial movement of said one element.

9. In combination in a transmission mechanism, a reversibly rotatable driving input member, a rotatably driven output member, and connecting means between said members including torque limiting means normally maintaining the torque at a predetermined value, and load responsive means to afiect said limiting means in either direction of rotation of said input membar to reduce said value upon imposition on said output member of a load greater than said value, the last said means including predetermined compressible means, a reversibly rotative member, means axially oppositely affected by said member in accordance with the direction of rotation thereof, and a member afiected in one direction in opposition to said compressible means to reduce said value in response to rotation of said reversibly rotative member in either direction.

AUGUST W. OFELDT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 975,846 Fensom Nov. 15, 1910 1,071,992 Ellett Sept. 2-, 1913 1,254,372 Stanley Jan. 22, 1918 1,409,090 Slasser Mar. 7, 1922 1,430,627 Cleland Oct. 3, 1922 1,636,009 Miller July 19, 1927 1,735,799 Smith Nov. 12, 1929 1,757,517 Eaton May 6, 1930 1,775,479 Arter Sept. 9, 1930 1,958,070 Schmid et al. May 8, 1934 1,959,042 Staley May 15, 1934 1,985,662 Lansing Dec. 25, 1934 2,241,639 Fitzgerald May 13, 1941 2,355,202 Cartlidge Aug. 8, 1944 2,371,855 Sunderland Mar. 20, 1945 

